Engine cooling system



oct. 10, 1939. I w GERSTUNG 2,175,432

ENGINE COOLING SYSTEM Filed May 2, 1938 I mum I 3nnentor v attome s Patented Oct. 10, 1939 UNITED STATES PATENT OFFICE 2,115,432 anon: COOLING srs'rm George W. Gerstung, Lockport, N. Y., assig'nor to General Motors Corporation, Detroit, Mich a corporation of Delaware Application May z, 1938, Serial No. 205,434

6 Claims.

' tem temperature, which in normal operation is also a measure of lubricating system temperature. I As a consequence a quick warm-up at the start a of engine operation is had and during the warmup period when the cooling medium in the engine and around the combustion chamber takes on heat faster than does the lubricating oil in the crankcase, heat from the cooling liquid passes through the heat exchanger common to both sysgo tems and into the lubricating oil.

Thisexchange of heat between the two systems avoids overheating of 'the cooling system and raises the temperature of the lubricating oil and -crankcase parts. As engine operatlon'continues 25 the oil.starts to take on heat from the crankcase parts and the rate of heat exchange between the two systems drops and finally dissipation of excess heat from both systems to an air stream is called for. To control heat disso sipation an air fiow valve is operated automatically under control of cooling liquid temperature beyond the heat exchanger.

For a better understanding of the invention reference may be made to the accompanying.

as drawing wherein Figure 1 is a side elevation showing thecooling system as installed in an airplane; Figure 2 is a front elevation of the structure shown in Figure 1; Figure 3 is a fragmentary view on a larger scale with parts in sec- 40 tion, showing, the radiator structure; Figure '4 is a detail sectional view taken on line |4 of Figure 5, and Figure 5 is a view with a part thereof shown in section as on line 5-4 of Figure 3.

' 45 In the drawing the reference numeral l in- The return connection for cooling medium from the heat exchanger or radiator is shown at I joined to a fitting 8 leading back to the engine jacket; A reserve storage tank 9 for cooling liquid outside. the circulating system is connected by the conduit II with the fitting I. Also asso- 6 ciated with the fitting I and acted on by cooling liquid from the cold side of the radiator is a thermostat unit Ii connected by suitable linkage to a rockshaft i2 for operating the shutter 'assembly I! which constitutes a damper valve con- 10- trolling air flow through the passageway 6. As shown in Figure 1 the radiator may comprise tandem sections ll-ll, each having an inlet tankor header ii for connection with the conduit .4 and an outlet header l6 for connec- 1 tion with the return line 'I. The inlet and outlet headers are connected for the flow of cooling liquid in thin streams by a series of spaced tubes, each provided with suitable radiating fins. Either orboth of the radiator sections may be constructed as shown in the detail views, Figures 3, 4 and 5, wherein the tube assembly is made up of a number of spaced tubes arranged in sets l1 and il', respectively, with the tubes of one set alternately disposed with reference to the other set. The set of tubes I! are in communication at one end with the inlet header I5 and at the other end with the outlet header ii. The tubes ll of the other set communicate at one end with a number of branches l9 leading from a 80 header Ill and similar branches connect the op-'- posite ends of the tubes it with a header 2|. The headers 20 and 2| as shown in the drawing may be in the form of conduits or connections/ with the engine lubricating system for the circulation of lubricating oil. Between the neighboring tubes are the spacers or separators 22 each in the form of a zigzag strip to aiford a series of-fins extending between adjacent tubes and dividing the space into a number of air cells. The surfaces of the 40 fins may contain any suitable formation or the fins may be louvered in a well known manner for action on the air stream so as to work the air particles to best advantage. At the start of engine operation when the shutters it are closed, heat from the cooling system is given up by the liquid fiowing through the tubes I1 and carried through the fins 22 into the liquid within the neighboring or alternately disposed tubes i8, thereby warming the oil and lowering its viscosity. 'Obviously, the two sets of tubesmay be scattered throughout the core assembly in other than ..the alternate arrangement referred to but for the quick transfer of heat best results are had when the transfer is between 86 g mostat ll starts to operate. Such-temperature is reached after the oil' temperature raises to a point where the heat transfer between the systems drops off and the cooling of oil becomes de- I sirable. Thereupon the shutters are open in accordance with heat rejection requirements for the flow of air through the passageway 8, due to plane travel or propeller action, and the extraction or dissipation of heat in the radiator from both the engine cooling liquid and lubricating oil.

The extent of cooling required for any given installation will determine the relative number and size of cooling tubes incorporated in the radiator for association with the respective systems to maintain a balanced temperature condition. With this in mind the drawing shows the alternate disposition of cooling system tubes and lubricating tubes, in only the forward section of the radiator assembly with the rearward section comprising the conventional radiator core in which all the tubes communicate with the upper and lower headers in the cooling system.

I claim: I

1. In combination, an engine having a lubricant circulating system and a cooling circulating system, an air cooled heat exchanger common to both systems and including a series of spaced tubes, heat transfer fins spacing and. joining neighboring tubes for heat flow between the tubes, a pair of headers communicating with alternate tubes as a part of the cooling system, a second pair of headers communicating as a part of the lubricating system with those tubes between the first mentioned tubes and temperature controlled means governing heat absorbing air flow over the tube and tin surfaces.

2. In an air cooled heat exchanger of the character described, a pair of inlet headers and a pair of outlet headers, a series of spaced tubes joining flow regulator.

one inlet header with one of the outlet headers, a second series of tubes extending in spaced parallelism with the first mentioned tubes between the other inlet and outlet headers and being dis posed in alternate relation with the first mentioned tubes and separators spacing the several tubes from one another for the fiow of cooling air through the spaces and constituting heat transfer fins between neighboring tubes.

3. A heat exchanger of the character described including an assembly of spaced tubes and heat transfer fins separating said tubes, a pair of headers communicating with each other through alternate tubes of the assembly and a second pair .of headers communicating with each other through the tubes located between the first mentioned tubes.

4- A heat exchanger of the character described including an assembly of spaced tubes and heat transfer fins separating said tubes, a pair of headers communicating with scattered tubes of the assembly and a pair of headers communicating with the remaining tubes.

5. In an engine temperature control system, a heat exchanger comprising an assembly of spaced parallel tubes and heat transfer fins between the tubes, engine lubricating system connections with certain of the tubes, engine cooling system connections with other of the tubes, means controlling the fiow of cooling air to said heat exchanger and a temperature responsive device associated with one of said connections for actuating the air flow control means.

6. In an engine temperature control system, a passage for the flow of cooling air, an air fiow regulator for said passage, an assembly of tubes positioned in said passage, separator fins spacing said tubes and serving for the transfer of heat between neighboring tubes and between the fin surfaces and air flowing through said passage, cooling system connections with alternate tubes of the assembly, lubricating system connections with the intervening tubes, and temperature responsive means associated with the cooling system connections controlling operation ofthe air GEORGE W. GERSTUNG. 

